II. C. FALL 
2S7 
is characteristic of normal examples of these two specie's. (\)n- 
Jinis is a somewhat larp:er species on the average, and the' elev- 
enth elytral stria is a little nearer the margin than in bifarins. 
These differences are, however, not relialile in all individuals, 
and the only sure test is the genitalic one. 
In a species so widely dispersed as hifarius, a consiilerablc 
amount of variation should be expected; this is especially no- 
ticeable in the size, form, luster and distinctness of the fine 
ground sculpture, 
1 1 . Gyrinus confinis LeConte 
.V little larger, slightly narrower and a little less convex than wuLralis-, 
entire upper surface with a feeble green bronze luster which is a little more 
pronounced at the margins. There is a very fine alutaceous sculpture and 
minute scattered punctulation, esi^ecially in the female, more easily detectable 
than in ventmlis, but still scarcely visible under low power. The lower sur- 
face is rufous or rufo-testaceous, sometimes quite uniform in tint, but often 
with the ventral segments in jiart darker. 
Male genilalia. Uniformly testaceous, median lobe a little narrower Ihati 
the lateral ones, strongly flattened horizontally and nearly parallel-sided for 
some distance before the apex, which is rounded or feebly angulate. 
Length, 5.7 to l>.7 mm.; width, 2.0 to 3.6 mm. 
Type locality . — Lake Superior. 
This species is known to me from Massachusetts (\\ ake- 
tield): New York (Chamnont River, Jefferson County; Wad- 
dington, St. Lawrence C’ounty; Ausai)le Point, Clinton ( ountj" 
— Notman): Ontario (Ottawa and Hull— Beaulne; Xepigon— 
Fenyes); iManitolia (Winnipeg; Le Pas; Husavick; Selkirk; 
Piquitenay River; Kettle Rapids — A\ allis) : (Montana (Mis- 
soula). 
From the above it will be seen that conjinii^ ranges from New 
Fngland to Alontana, occ'upying nearly the same territory as 
vcntra(i!<. 
12. Gyrinus plicifer LeConte 
Form rather broad and thick, ai)i)roaching in these r(‘sp(>cts and in genend 
tacies the still somewhat stouter pactnysoniiis of the Atlantic region. C'olor 
above black, the sides broadly bronzed, the surface highly polished and with- 
out trace of alutaceous .sculpture in either sex. Strial i)unctures of the elytra 
distinctly larger laterally than near the suture, the eleventh stria rather close 
to the margin; outer apical angle of the elytra with a short elevated plica 
close to the margin. Body beneath brownish red varying to dark castaneou>. 
the cpipleura commonly ol a brighter rufous tint. 
TU.\XS. AM. ENT. SOC., XLVII. 
